Cathode active material for lithium secondary battery and lithium secondary battery including the same

A cathode active material for a lithium secondary battery, comprising:

• a lithium-transition metal composite oxide particle consisting of a structure in which a plurality of primary lithium-transition metal composite oxide particles are integrally merged together and are thermally converted into a single lithium-transition metal composite oxide particle without pores;
• a first coating layer formed on a surface of the lithium-transition metal composite oxide particle, the first coating layer comprising a La—Zr—O compound;
• and
• a second coating layer formed on a surface of the first coating layer, the second coating layer comprising a Li—B—O compound,
• wherein an average particle diameter, D50, of the lithium-transition metal composite oxide particle is 2.0 μm or more, and
• wherein the average particle diameter, D50, is the particle diameter at 50% cumulative volume in the particle size distribution.